Gender-Dependent Associations Between Digit Ratio and Genetic Polymorphisms, BMI, and Reproductive Factors

INTRODUCTION

, serving estrogen wer stosterone and

the before

categories of pathologies, ranging from

such as Insulin, IGF2, angiotensin I- yme (ACE), angiotensin II type 1

receptor (AT1R), vitamin D receptor (VDR), and IL-6 genes may imply fetal growth and development and have been associated with

Insulinthe human placenta and it may be implicated in insulin-regulated

-angiotensin-aldosterone system (RAAS), responsible for homeostasis, s, -reported biomarker for

hypertension and AT1R A1166C was strongly associated with the risk of developing pregnancy-

al density, d sex hor ns the t plays a the studied VDR polymorphisms may be of interest: VDR Fok I (C/T), VDR ApaI (A/C), has been reported in the literature so far.

• – Having pro-6 was associated with right ILrque Teno viruses (TTV) – evelopment, although studies

t, BMI, and

, and a series of common polymorphisms.

MATERIALS AND METHODS

Selection of subjects.

All

participants were informed about the purpose of the study. Selection criteria for the participants included alcohol intake and smoking. Alcohol intake consisted of no more than two standard drinks a day for men and one standard drink a day for women. A beverage is king, the threshold

Methods and Protocols.

The length between the second digit and the fourth digit was measured by the caliper three times, therefore the value obtained is the average of these three consecutive measurements. It was measured on the ventral surface of the left hand, from a midpoint on the metacarpophalangeal flexion crease to the tip of the digit. The measurements were considered valid if the difference between the maximum and minimum values measured for a finger was less than 5 mm. If the difference was greater, the measurement process -1.005, with more extreme values excluded.

A peripheral blood sample (300 mL) was collected from each subject in an EDTA tube and genomic DNA was extracted using the – I/D p -RFLP technique was used for -23 Hph I (- -6 – the tetra-primer ARMS-

Statistical Analysis.

The distribution of qualitative data in subgroups of subjects was with Chi-square or Fisher tests. The outlier values for 2D:4D were considered values that one-way ANOVA with post-hoc Tukey HSD test. Simple linear regression analyses were used to assess the variation in anthropometric parameters with variation in 2D:4D. The statistical analyses were performed using the R Studio software, version 2023.12.1.+402. ere considered statistically significant if p<0.05.

RESULTS

• – – – -1.01) of subjects were estimated. The characteristics of the investigated subjects are presented in Table 1.

We have identified no outliers for 2D:4D in the case of men or women investigated in this study. Men have a higher digit ratio than

a p<0.05; b p<0.0001

The IGF2 GG and ACE DD were associated with a higher digit ratio in all subjects and also in women (Table 2). No other genotype shows a significant association with the digit ratio.

a p<0.05; b p<0.01; c p =0.006

The INS and IGF2 (11p15.5) polymorphisms or VDR (12q13.11) polymorphisms were mapped in close proximity. As a consequence, we evaluated the effects of Ins -23 Hph – IGF2 Apa I and VDR Fok I – Apa I – Taq I haplotypes on 2D:4D. The INS-23 Hph I – IGF2 Apa I T- associations were identified between the digit ratio and VDR Fok I – Apa I – Taq I haplotypes (Table 3).

Twenty-

<0.05)

(Figure 1). The average age at which they had their first child was similar between those who had one child and those who had multiple

The 2D:4D values were lower in women who had no children compared to those who had children (p <0.001), who had at least two t between men who had at least two children and those who had one child (p<0.001) or who did not have children (p<0.02). In the subset of , p< 0.001). The height of men and women stratified by the number of children did not show any statistically significant differences (Figure 2).

(Haplotypes with frequency <0.03 were not taken into consideration;^a p <0.01)

<!– Start of picture text –> 1.005<br>1.000<br>0 1 0 1<br>Men Women<br>Number of children<br><!– End of picture text –>

The 2D:4D values were higher in overweight subjects than in normal2 men compared to women. Each gender was subsequently stratified according to BMI into normal-weight and overweight subgroups. There was only a significant difference between the 2D:4D values of overweight men and normal-

p<0.05). No significant results were found when the male and female subsets were stratified according to height.

There appears to be a positive correlation between 2D:4D and BMI, regardless of gender (F=0.02) (Figure 3), and an inverse correlation between the 2D:4D and height of men (F = 0.03) (Figure 4). However, the proportion of 2D:4D variance that may be predicted based on BMI (R2=0.047) or height (R2 =0.08) appears to be weak.

similar in women stratified by parity.

<!– Start of picture text –> y = -0.0008x + 1.125 y = -<br>R² = 0.0804 R² = 0.0213<br><!– End of picture text –>

<!– Start of picture text –> y = -0.0008x + 1.125 y = -<br>R² = 0.0804 R² = 0.0213<br><!– End of picture text –>

<!– Start of picture text –> Men 2D:4D Women 2D:4D<br>Men – linear regression Linear (Men 2D:4D )<br><!– End of picture text –>

DISCUSSION

2D:4D ratio in 327 deceased fetuses (14 to 42 weeks old) concluded that the values were lower than those reported for children and this ratio can change, to a some extent the length between the index and ring fingers. In the present study, the 2D:4D values were not correlated with age, neither at the level of the entire group of adult participants nor at the subgroup level by gender. The difference between genders appears to be moderated by the type of finger length measurement and by the hand that was measured. Some studies suggest that there are greater differences between genders when measurements are taken on the right hand, which 0.05). This re -analysis that studied the representation of women in politics and was based on data collected in an online survey, the reported data for Romania indicated higher values in women than in

The difference between genders appears to be moderated by the type of finger length measurement and by the hand that was measured. Some studies suggest that there are greater differences between genders when measurements are taken on the right hand, which

In contrast to the 2D:4D, height, weight, and BMI are characteristics that change postnatally, influenced by both genetic and environmental factors. Weak correlations between 2D:4D and these variables were identified in this study. Studies are not consistent r studies

The analysis of anthropometric data we performed showed that the values for weight and BMI were higher in men than in women. Moreover, we identified a significant difference between the 2D:4D values of overweight men and normaland ferences r males (F = 0.03), but not for females or both genders. One study reported that body height was negatively correlated with right- and left-hand digit ratios and the correlations were significant for the left-hand digit ratio in men and for the right-hand digit ratio in

and ferences r

Our data suggested a significant association between 2D:4D and reproductive success which is influenced by gender. Thus, lower average 2D:4D values were recorded in women who reported a pregnancy loss or who had no or one child (p <0.001). In the case of men lower 2D:4D values were associated with a higher number of children. Our results are in agreement with some results reported

consistent with those previously reported in the Romanian population. Previous studies have reported that the IGF2 G allele may contribute to orphisms in the IGF2 gene region, concluded that IGF2 genetic variation is a significant determinant of body weight in middledata we have obtained suggest that nearby genes, IGF2 or Insulin, could influence the digit ratio. The IGF2 GG genotype was associated with a higher digit ratio, especially in women (p<0.05) whereas the Insulin – IGF2 T-G haplotype was significantly associated with 2D:4D, but only in men. The closely linked IGF2 and Insulin genes have been previously associated with various conditions such as the association between the parent-of-origin allele and various phenotypes. The design of our study did not permit the investigation of IGF2 parent-of-origin.

ACE converts angiotensin I into angiotensin II and most of its functions are mediated by AT1R. ACE D was associated with a higher d especially in women (p<0.01). In a previous study, ysical endurance or I/D polymorphism and 2D:4D ratio might play a role in cardiovascular pathology, our subjects (42-60 years old), although clinically healthy, may still have a predisposition to develop these diseases. This predisposition might influence the results obtained in this study, potentially causing a bias. The results could also be affected by the small number of subjects included in the study (n=120), as well as by measurement errors related to the length between the index and ring fingers.

Although no significant association was identified between the digit ratio and Torque Teno viruses, the high prevalence of TTV in the

CONCLUSION

In our dataset, the digit ratio was similar in men and women. The data obtained in this study indicated that INS – IGF2 T-G haplotype, ACE I/D, pregnancy loss, number of children, and BMI are associated with digit ratio. These relations could be also influenced by the gender of the subject. Additional studies are needed to bring new data regarding the relationships between 2D:4D and the genetic polymorphisms of anthropometric characteristics to see if the results we obtained in this study could be replicated. This data could contribute to a broader understanding of how genetics can shape developmental outcomes through prenatal hormones.

Conflicts of interest and sources of funding

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results. This study was funded by the Ministry of Research and Education, grant number PN 23 01 03 03.

Acknowledgment

The current manuscript does not contain previously published materials or self-generated AI text.

Authors’ contribution

Conceptualization, N.S., R.S., R.M., and D.C.; methodology, O.C.; software, R.M. and M.T.; validation, M.I.N., M.L.C., and C.I.; formal analysis, M.T and M.I.N.; investigation, N.S., D.C., L.B., O.A.; resources, L.B., D.C.; data curation, S.R. and O.A..; writing—original draft preparation, N.S., E.S., R.M, O.C.; writing—review and editing, D.C., M.T, I.R., M.L.C.; visualization, M.T.; supervision, D.C. and O.C.; project administration, L.B, and D.C.; funding acquisition, L.B. and S.R.. All authors have read and agreed to the published version of the manuscript

Ethics approval and consent to participate

The study was conducted in accordance with the Declaration of Helsinki, and approved by the Ethics Committee of the National Research and Development Institute for Food Bioresources – IBA Bucharest (protocol code 285/20.03.2023).

Patient consent for publication

Informed consent was obtained from all subjects involved in the study.

References

26. – –

-021-86521-7.

27. Blomberg Jensen M, Nielsen JE, Jørgensen A, Rajpertare expressed in the human male reproductive tract. Hum. Reprod. 2010, 25, 5, 1303– 28. Engelmann M, Landgraf R, Wotjak CT. The hypothalamic–neurohypophysial system regulates the hypothalamic–pituitary–adrenal axis under stress: An old concept revisited. Front. Neuroendocrinol. 2004, 25, 3–4, 132–

Portnoy J, Raine A, Glenn AL, Chen FR, Choy O, Granger DA. Digit ratio (2D:4D) moderates the relationship between cortisol reactivity and self–106, DOI: 10.1016/j.biops 30. Combs C. A, Garite TJ, Lapidus JA, Lapointe JP, Gravett et al. Detection of microbial invasion of the amniotic cavity by analysis of cervicovaginal proteins in women with preterm labor and intact membranes. Am. J. Obstet. Gynecol. 2015, 212, 482.e1–482.e12, DOI:10.1016/j.ajog.2015.02.007

31. -Giannikou E et al. “Healthy Growth Study” Group. The correlation of right 2D:4D finger length ratio to the low-grade inflammation marker IL-6 in children. The Healthy Growth Study. Early Hum Dev. 201 -65. DOI: 10.1016/j.earlhumdev.2013.10.003.

32. Sabbaghian M, Gheitasi H, Shekarchi AA, Tavakoli A, Poortahmasebi V. The mysterious anelloviruses: investigating its role in human diseases. BMC Microbiol. 2024, 24, 1, 40.

33. Spandoleommon pathologies. BMC Infect Dis, 2018, 18, 334.

34. Saback FL, Gomes SA, de Paula VS, da Silva RR, Lewis–322.

35. Tyschik EA, Shcherbakova SM, Ibragimov RR, Rebrikov DV. Transplacental transmission of torque teno virus. Virol J. 2017, 14, -017-0762-0. 36. Gore EJ, Gard L, Niesters HGM, Van Leer Buter CC. Understanding torquetenovirus (TTV) as an immune marker. Front Med, 2023, 13 10, 1168400.

37.

38. vel human – Rigat B, Hubert C, Corvo P., Soubrier F. PCR detection of the insertion/deletion polymorphism of the human angiotensin conver

40. e growth factor II 41. Santoro N, Cirillo G, Amato A, Luongo C, Raimondo P et al. Insulin Gene Variable Number of Tandem Repeats (INS VNTR) Genotype and Metabolic –4644, 10.1210/jc.2005-2705 42. 3.8.1444 43. orphism in the -632, DOI: 10.1203/00006450-00002 44. e determination of – 100622

45.

46. Shi Y, He L. SHEsis, a powerful software platform for analyses of linkage disequilibrium, haplotype construction, and genetic association at – 47. Galis F, Ten Broek CMA, Van Dongen S, Wijnaendts LCD. Sexual dimorphism in the prenatal digit ratio (2D:4D). Arch Sex Behav, -62, DOI: 10.1007/s10508-7. 48. Trivers R, Manning J, Jacobson A. A longitudinal study of digit ratio (2D:4D) and other finger ratios in Jamaican children. H 150-156. DOI: 10.1016/j.yhbeh.2005.05.023.

Hönekopp J, Watson S. Meta-630, DOI: 10.1002/ajhb.21054.

50. Manning, JT, Fink B, Trivers R. Digit Ratio (2D:4D) and Gender Inequalities Across Nations. Evol Psych, 2014, 12, 4, 757-768, 51. Manning JT, Fink B, Mason L, Trivers R. Digit ratio (2D:4D) and body mass index in the BBC Internet Study: prenatal sex steroids and a TriversWillard effect on body composition. J Biosoc Sci. 2021, 1–

52. Peeters MW, Claessens AL. The left hand second to fourth digit ratio (2D:4D) does not discriminate world-class female gymnasts from age matched sedentary girls. PLoS One. 2012, 7, 6, e40270. DOI: 10.1371/journal.pone.0040270.

53. ications in Obesity – A Cross Sectional Study. Indian J Endocrinol Metab. 2018, 22, 6, 724-727. DOI: 10.4103/ijem.IJEM_414_18.

54. – with birth weight, BMI and muscle strength in 6- to 13-year-old Polish children. PLoS ONE, 2021, 16, 10, e0

55. Ergul EO. Relationships between the 2D:4D digit ratio, waist circumference, hand preferences, weight, height, waist-to-height ratio and BMI in a -1304.

56. Zenoaga-Dimov T, Toma M, Nica MI et al. The Predisposition for Type 2 Diabetes Mellitus and Metabolic Syndrome.

Balkan J Med Genet. 2023, 26, 1, 21-26. DOI: 10.2478/bjmg-2023-0003.

57. Nica R, Berca L-M, Mosoiu C-E, Nica S. Distribution of eleven markers in South Romanian (Walachia region) population. Rom Biotechnol Lett. 2020, 25, 2, 1424-1431. DOI: 10.25083/rbl/25.2/1424.1431. 58. Cimponeriu D, Apostol P, Radu I, Craciun AM, Serafinceanu C, Toma M et al. The insulin polymorphism -23Hph increases the risk for type 1 diabetes mellitus in the Romanian population. Genet Mol Biol. 2010, 33, 4, 610-47572010005000074.

Bachner-Melman R, Zohar AH, Nemanov L, Heresco-Levy U, Gritsenko I, Ebstein RP. Association between the insulin-like growth factor 2 gene (IGF2) and scores on the Eating Attitudes Test in nonclinical subjects: a family-based study. Am J Psychiatry. 2005, 162, 12, 2256-2262. DOI: 10.1176/appi.ajp.162.12.2256.

60. gene region and – 61. -INS-TH gene cluster in relation to cardiovascular risk traits. Hum Mol Genet. 2004, 13, 7, 71562. -INS-TH region of human chromosome 11. Hum Genet. 2002, 110, 2, 173-001-0663-5.

63. Pidsley R, Fernandes C, Viana J, Payamass in outbred mice. Mol Brain, 2012, 5, 42. DOI: 10.1186/1756-6606-5-42.

64. Zhao Q, Fan Y, Tang N, Zhang Z, Fang Z. The ACE I/D polymorphism and its association with serum ACE activity and circulating inflammatory -578. DOI: 10.1038/jhh.2017.30.

65. Manning JT, Fink B. Understanding COVIDcase fatality rates. Early Hum Dev. 2020, 151, 105161. DOI: 10.1016/j.earlhumdev.2020.105161.

66. Luo Z. Impacts of ACE insertion/deletion variant on cardiometabolic risk factors, premature coronary artery disease, and severity of coronary -024-64003-w. 67. Cam FS, Colakoglu M, Sekuri C, Colakoglu S, Sahan C, Berdeli A. Association between the ACE I/D gene polymorphism and physical performance in a homogeneous non-elite cohort. Can J Appl Physiol. 2005, 30, 1, 74-106.

68. Spandole-Dinu S, Cimponeriu D, Stoica I, Apircioaie O, Gogianu L, Berca LM, Nica S, Toma M, Nica R. Phylogenetic analysis of torque teno virus in Romania: possible evidence of distinct geographical distribution. Arch Virol. 2022, 167, 11, 2311-2318. DOI: 10.1007/s00705-022-8.